3.35pm: The Associated Press is reporting that the explosion tore through the international arrivals hall at Domodedovo airport in Moscow (below is a map of where the airport is).

AP reports: "The state RIA Novosti news agency, citing sources in law enforcement, said the explosion at Domodedovo Airport may have been caused by a suicide bomber."

The news agency says Moscow police have been put on high alert and have beefed up their patrols on the city's underground train system, a previous target for terrorists.

Mark Green, a British Airways passenger who had just arrived at the airport, told BBC television he heard the huge explosion as he was leaving the terminal:

Literally, it shook you. As we were putting the bags in the car a lot of alarms ... were going off and people started flowing out of the terminal, some of whom were covered in blood. One gentleman had a pair of jeans on that was ripped and his thigh from his groin to his knee was covered in blood.

He said thousands of people were in the terminal at the time of the blast.

AP provides some context about the Domodedovo airport, which is regarded as Moscow's most up to date hub, but its security procedures have been called into question:

In 2004, two suicide bombers were able to board planes at Domodedovo by buying tickets illegally from airport personnel. The bombers blew themselves up in mid-air, killing all 90 people aboard the two flights.

Built in 1964, Domodedovo is located 26 miles (42 km) southeast of the centre of Moscow and is the largest of the three major airports that serve the Russian capital, serving over 22 million people last year.

Terrorists have targeted other transport centres in Moscow.

In more recent suicide bombings, twin blasts on the underground last March killed 39 people and wounded more than 60 people.

In December 2009, Chechen rebels claimed responsibility for blowing up a high-speed train between Moscow

Dmitry Medvedev is delaying his planned trip to Davos because of the bombing, BBC News is reporting.

3.34pm: BMI airline operates two flights daily into Domodedovo airport. A spokeswoman said flight BD891 landed at 4.30pm local time with 97 passengers on board.
She said all the passengers had disembarked before the incident happened.

All the BMI crew are accounted for. We are waiting for information about whether the passengers were caught up in the incident from the authorities in Moscow.

3.33pm: Here is a timeline of previous terrorist attacks on Russia.

3.32pm: The Foreign Office is "urgently investigating" whether any British nationals may have been caught in the Russian airport bombing; there are no reports of any British people being affected at the moment.

A Foreign Office spokeswoman said:

We've seen reports of an explosion at Domodedovo airport in Moscow and are urgently investigating. Consular staff including the consul general are on their way to the airport. We are making contact with the Russian authorities to see exactly what has happened. We are also making contact with the British airlines using Domodedovo. There are no reports yet of injured British nationals.

3.30pm: Dmitry Medvedev, the Russian president, has vowed to track down and punish those behind the attack, which took place at Russia's biggest airport.

Writing on Twitter, Medvedev said:

Security will be strengthened at large transport hubs. We mourn the victims of the terrorist attack at Domodedovo airport. The organisers will be tracked down and punished.

3.23pm: At least 31 people have been killed and scores injured in a suspected suicide bomb blast at Moscow's Domodedovo airport today, according to reports.

The Russian state news agency said around 130 people have been injured in the explosion.
Smoke was seen billowing out of the baggage claim area with people running out of the emergency exits at the airport, local media reported.

A traveller, identified as Viktor, told the Russkaya Sluzhba Novostei radio station:

There was an explosion, a bang. Then I saw a policeman covered in fragments of flesh and all bloody. He was shouting: "I've survived! I've survived!"

The Investigative Committee confirmed the blast at Domodedovo Airport and, in a post on its website, blamed it on a terrorist act. But the committee listed the number of injuries only at "more than 20" and did not say how many had died.

State TV said the explosion occurred at the baggage claim area of the airport.

The explosion occurred at 4:40 p.m., the official RIA Novosti news agency reported.

Domodedovo is located 22 kilometers southeast of Moscow. According to the airport's website, it is the largest of Moscow's three airports, as well as the busiest in terms of passenger traffic.

Explosion Shakes Moscow's Busiest Airport

(AP)

MOSCOW — An explosion shook the busiest airport in the Russian capital on Monday afternoon and an aviation official said an unspecified number of people were killed.

There was no immediate word on the cause of the explosion in the international baggage-claim area at Domodedovo airport.

Russia's Investigative Committee said there were at least 20 casualties in the blast and the state news agency RIA Novosti quoted a spokesman for the Russian aviation agency, Sergei Izvolsky, as saying there were dead among the casualties.